Hepatitis C virus (HCV) infection leads to chronic liver disease such as cirrhosis and hepatocellular carcinoma. So far, HCV infection is one of the major infection diseases, due to the fact that the number of HCV infected individuals is estimated 5-15% of the world's population while no any effective vaccines or therapeutic agents are available, so how to control or cure HCV is an urgent human health problem needed to be solved. [Reference: WO 89/04669; Lavanchy, J. Viral Hepatitis, 6, 35-47 (1999); Alter, J. Hepatology, 31 (Suppl. 1), 88-91 (1999); and Alberti et al, J. Hepatology, 31 (Suppl. 1), 17-24 (1999)].
Currently, due to lack of immunity or remission associated with HCV infection, hepatitis caused by HCV infection is more difficult to treat comparing to other forms of hepatitis. Now, the only available anti-HCV therapies are interferon-α, interferon-α/ribavirin combination, and pegylated interferon-α. However, sustained response rates for interferon-α or interferon-α/ribavirin combination were found to be <50% and patients suffer greatly from side effects of these therapeutic agents [Reference: Walker, DDT, 4, 518-529 (1999); Weiland, FEMS Microbial. Rev., 14, 279-288 (1994); and WO 02/18369]. Now, a linear molecule HCV inhibitor VX950 as a HCV new drug from Vertex (US) is expected to be approved during second half of 2011, which can control and cure HCV infection but the activity to inhibit HCV is quite low while the dosage is high and the side effects are potential. Besides, some patients could have antibodies, so it is necessary to develop more effective therapeutic drugs with lower dosage and side effects for inhibiting HCV.
So far, Hepatitis C virus (HCV) is the major causative agent for most cases of non-A, non-B hepatitis, and it is a single-stranded positive RNA virus in the Flaviviridae family. It includes a nucleocapsid protein (C), envelope proteins (E1 and E2), and several non-structural proteins (NS1, NS2, NS3, NS4a, NS5a, and NS5b). The NS3 protein possesses serine protease activity and is considered essential for viral replication and infectivity, and the essentiality of the NS3 protease was inferred from the fact that mutations in the yellow fever virus NS3 protease decreased viral infectivity [Reference: Chamber et al, Proc. Natl. Acad. Sci. USA 1990, 87, 8898-8902; Rice et al, J. Virol. 2000, 74 (4) 2046-51]. Furthermore, the HCV NS3 serine protease has been found to facilitate proteolysis at the NS3/NS4a, NS4a/NS4b, NS4b/NS5a, NS5a/NS5b junctions and is thus responsible for generating four viral proteins during viral replication [Reference: US 2003/0207861]. Consequently, the HCV NS3 serine protease enzyme is an attractive and effective target to develop new inhibitors for HCV infection.
Many European and American research institutes and pharmaceuticals have deeply and widely developed different kinds of the linear and cyclic molecules as HCV inhibitors since 1999. Some representative potential NS3 HCV protease inhibitors have been reported in patents and articles, such as WO2010033466, WO2010075127, US20100003214, US20100022578, US20100029715, US20100041889, WO2009134624, WO2009010804, US20090269305, WO2008057209, WO2008057208, WO2007015787, WO2005037214, WO200218369, WO200009558, WO200009543, WO199964442, WO199907733, WO199907734, WO199950230, WO199846630, WO199817679, U.S. Pat. No. 5,990,276, Dunsdon et al, Biorg. Med. Chem. Lett. 2000, 10, 1571-1579; Llinas-Brunet et al, Biorg. Med. Chem. Lett. 2000, 10, 2267-2270; and S. LaPlante et al., Biorg. Med. Chem. Lett. 2000, 10, 2271-2274.
Besides, other HCV NS3 protease inhibitors such as a kind of macro-cyclic peptide compounds were derived from bicyclic rings formed by one aromatic ring and another saturated heterocyclic ring on HCV NS3 protease P2 site, which was reported in patent US2005/0267018 of InterMune. The patent WO2007/016476 of Phenomix published in 2007 disclosed a linear peptide compound formed by connection of special boric acid on HCV NS3 protease P1 site; The patent WO2007/014920 of Tibotec and Medivir published in 2007 disclosed a macro-cyclic peptide compound derived from N-serined carbamates; The patent WO2008/074035 of Abbott published in 2008 disclosed a linear peptide compound derived from special cycloalkanes; The patent WO2008/106130 of Achillion published in 2008 disclosed a linear and macro-cyclic peptide derived from special piperidines; The patent WO2008/134397 of Enanta published in 2008 disclosed a linear peptide compound derived from connection of hydrazine groups on HCV NS3 protease P3 site; Also, The patent WO2008/057209 of Merck published in 2008 disclosed a macro-cyclic peptide compound by connection of aromatic rings on HCV NS3 protease P2 site.
So far, some different kinds of macro cyclic HCV inhibitors were developed by famous global pharmaceuticals have entered into Phase III in the US, EU and in Japan, such as ITMN-191 (RG-7227) of InterMune (US) and MK-7009 of Merck (US) by Structure Figure 1. Other potent molecules ZN2007, ZN2012 and ZN2017 (Reference: CN102140100 A; US2011/0183895 A1; WO2011/091757 A1) were developed by Zannan to inhibit HCV, is now taking the pre-clinical research. The character of Zannan's macro-heterocyclic HCV drugs is to design a macro-cyclic molecule by synthesis of 14-20 membered macrocyclic molecules prepared by both amido bond and olefin double-bond.
